1. Technical Field
The present disclosure relates to a liquid-crystal display device and an electronic apparatus.
2. Description of the Related Art
Liquid-crystal display devices include transmissive-type liquid-crystal display devices that display an image by using transmission light from a backlight provided on a backside of a screen. Some of this type of liquid-crystal display devices control brightness and darkness of a pixel with 0 to 255 gradations (so-called “256 gradation” or “8 bit display”) (see Japanese Patent Application Laid-Open No. 2007-219392). In the liquid-crystal display device, when an ambient temperature is low, a response speed of a liquid crystal is decreased. Therefore, in order to improve the response speed of the liquid crystal, the liquid-crystal display device performs so-called “overdrive” in which a driving voltage for driving the liquid crystal is set to a voltage higher than a normal driving voltage.
Some liquid-crystal display devices improve the responsiveness of the liquid crystal by using a range that exhibits a fast response of the liquid crystal, when the liquid-crystal display device is used under an ambient temperature that decreases the responsiveness of the liquid crystal (see Japanese Patent Application Laid-Open No. 2010-109578). Specifically, in this type of liquid-crystal display device, a range that exhibits a fast response of the liquid crystal is set such that a black level becomes 15% of brightness of the liquid-crystal display device and a white level becomes 85% of the brightness of the liquid-crystal display device.
In this manner, when the response speed of the liquid crystal is decreased in a low ambient temperature, the liquid-crystal display device improves the response speed of the liquid crystal by performing an overdrive that applies a driving voltage higher than a target driving voltage corresponding to a target gradation in order to render a gradation of a pixel to meet a target gradation. In this case, an application time of the driving voltage applied at the time of performing the overdrive is increased as the response speed of the liquid crystal is decreased. The liquid-crystal display device performs a display operation at a frame rate with which the number of frames per unit time is equal to a predetermined value, and applies a predetermined driving voltage for each frame cycle. Therefore, when the application time of the driving voltage is increased at the time of performing the overdrive, the liquid-crystal display device needs to increase the number of frames to be applied with the driving voltage. As a result, because the number of frames used in the overdrive is increased, a load on a driving circuit unit that drives each pixel is also increased.
As described above, there is a need for a liquid crystal display device that can improve the display quality at the low ambient temperature, and an electronic apparatus including the same.